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/*
Example code compatible with the Lambda Shield 2 for Arduino and GUI frontend.
Copyright (C) 2018 - 2021 Bylund Automotive AB
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Contact information of author:
http://www.bylund-automotive.com/
info@bylund-automotive.com
Version history:
2018-01-20 v1.0.0 First release.
2019-04-19 v1.0.1 Published on Github.
2019-06-26 v1.1.0 Adjusted PID regulation of heater.
2019-07-18 v1.2.0 Code optimization.
2020-04-12 v1.3.0 Modified serial output.
2021-01-04 v1.4.0 Added display and analog output support.
*/
//Define included headers.
#include <SPI.h>
#include <U8g2lib.h>
//Define CJ125 registers used.
#define CJ125_IDENT_REG_REQUEST 0x4800 /* Identify request, gives revision of the chip. */
#define CJ125_DIAG_REG_REQUEST 0x7800 /* Dignostic request, gives the current status. */
#define CJ125_INIT_REG1_REQUEST 0x6C00 /* Requests the first init register. */
#define CJ125_INIT_REG2_REQUEST 0x7E00 /* Requests the second init register. */
#define CJ125_INIT_REG1_MODE_CALIBRATE 0x569D /* Sets the first init register in calibration mode. */
#define CJ125_INIT_REG1_MODE_NORMAL_V8 0x5688 /* Sets the first init register in operation mode. V=8 amplification. */
#define CJ125_INIT_REG1_MODE_NORMAL_V17 0x5689 /* Sets the first init register in operation mode. V=17 amplification. */
#define CJ125_DIAG_REG_STATUS_OK 0x28FF /* The response of the diagnostic register when everything is ok. */
#define CJ125_DIAG_REG_STATUS_NOPOWER 0x2855 /* The response of the diagnostic register when power is low. */
#define CJ125_DIAG_REG_STATUS_NOSENSOR 0x287F /* The response of the diagnostic register when no sensor is connected. */
#define CJ125_INIT_REG1_STATUS_0 0x2888 /* The response of the init register when V=8 amplification is in use. */
#define CJ125_INIT_REG1_STATUS_1 0x2889 /* The response of the init register when V=17 amplification is in use. */
//Define pin assignments.
#define CJ125_CS_PIN 10 /* Pin used for chip select of CJ125 in SPI communication. */
#define LED_STATUS_POWER 7 /* Pin used for power the status LED, indicating we have power. */
#define LED_STATUS_HEATER 6 /* Pin used for the heater status LED, indicating heater activity. */
#define HEATER_OUTPUT_PIN 5 /* Pin used for the PWM output to the heater circuit. */
#define ANALOG_OUTPUT_PIN 3 /* Pin used for the PWM to the 0-1V analog output. */
#define UB_ANALOG_INPUT_PIN 2 /* Analog input for power supply.*/
#define UR_ANALOG_INPUT_PIN 1 /* Analog input for temperature.*/
#define UA_ANALOG_INPUT_PIN 0 /* Analog input for lambda.*/
//Define adjustable parameters.
#define SERIAL_RATE 10 /* Serial refresh rate in HZ (1-100)*/
#define UBAT_MIN 150 /* Minimum voltage (ADC value) on Ubat to operate */
#define hardwareId 0x00 /* The hardwareId defines which hardware you are using. */
//Global variables.
int adcValue_UA = 0; /* ADC value read from the CJ125 UA output pin */
int adcValue_UR = 0; /* ADC value read from the CJ125 UR output pin */
int adcValue_UB = 0; /* ADC value read from the voltage divider caluclating Ubat */
int adcValue_UA_Optimal = 0; /* UA ADC value stored when CJ125 is in calibration mode, λ=1 */
int adcValue_UR_Optimal = 0; /* UR ADC value stored when CJ125 is in calibration mode, optimal temperature */
int HeaterOutput = 0; /* Current PWM output value (0-255) of the heater output pin */
int CJ125_Status = 0; /* Latest stored DIAG registry response from the CJ125 */
int serial_counter = 0; /* Counter used to calculate refresh rate on the serial output */
int HeaterStatus = 0; /* Defines the heater status for the GUI front-end */
//PID regulation variables.
int dState; /* Last position input. */
int iState; /* Integrator state. */
const int iMax = 250; /* Maximum allowable integrator state. */
const int iMin = -250; /* Minimum allowable integrator state. */
const float pGain = 120; /* Proportional gain. Default = 120*/
const float iGain = 0.8; /* Integral gain. Default = 0.8*/
const float dGain = 10; /* Derivative gain. Default = 10*/
//Define display.
U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);
//Company logo bitmap.
PROGMEM const unsigned char Logo[] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0xff, 0xf8, 0x07, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x7f, 0xf8,
0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0xf8, 0x7f, 0xfc, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0x3f, 0xfc, 0x01, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfc, 0x3f, 0xfe,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0xfc, 0x1f, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7f, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x7f,
0x7f, 0x80, 0xfb, 0x07, 0xf8, 0x87, 0x3f, 0xff, 0x01, 0xe7, 0xff, 0x7f,
0x00, 0xfc, 0x8f, 0x3f, 0xff, 0xc0, 0xf1, 0x07, 0xf8, 0xc7, 0x3f, 0xfe,
0x81, 0xc7, 0xff, 0x7f, 0x00, 0xff, 0xc7, 0x3f, 0xff, 0xf0, 0xf8, 0x03,
0xf8, 0xc3, 0x1f, 0xfe, 0x81, 0xc3, 0x1f, 0xff, 0x80, 0xff, 0xc3, 0x1f,
0xfe, 0x78, 0xf8, 0x03, 0xf8, 0xe3, 0x1f, 0xff, 0xc1, 0xe3, 0x0f, 0x7f,
0xc0, 0xff, 0xe3, 0x1f, 0xfe, 0x1c, 0xfc, 0x01, 0xfc, 0xe1, 0x8f, 0xff,
0xc1, 0xe1, 0x8f, 0x7f, 0xc0, 0xff, 0xe1, 0x0f, 0xfe, 0x0e, 0xfc, 0x01,
0xfc, 0xf1, 0x87, 0xff, 0xe3, 0xf1, 0x87, 0x3f, 0xe0, 0xff, 0xf1, 0x07,
0xfe, 0x07, 0xfe, 0x00, 0xfe, 0xf0, 0xc7, 0xff, 0xe3, 0xf0, 0xc7, 0x3f,
0x00, 0x00, 0xf0, 0x07, 0xfe, 0x03, 0xff, 0x00, 0xff, 0xf8, 0xc3, 0xf9,
0xf3, 0xf8, 0xc3, 0x1f, 0x00, 0x00, 0xf8, 0x03, 0xfe, 0x01, 0x7f, 0x00,
0x7f, 0xf8, 0xe3, 0xf9, 0x73, 0xfc, 0xe3, 0x0f, 0x00, 0x00, 0xfc, 0x03,
0xfe, 0x80, 0x7f, 0x80, 0x7f, 0xfc, 0xe1, 0xf8, 0x3b, 0xfc, 0xe1, 0x0f,
0xf0, 0x7f, 0xfc, 0x01, 0xff, 0x80, 0x3f, 0x80, 0x3f, 0xfe, 0xf1, 0xf8,
0x3f, 0xfe, 0xf1, 0x07, 0xf8, 0x3f, 0xfe, 0x01, 0x7f, 0xc0, 0x3f, 0xc0,
0x3f, 0xfe, 0x70, 0xf8, 0x1f, 0xfe, 0xf8, 0x07, 0xfc, 0x3f, 0xfe, 0x80,
0x3f, 0xc0, 0x1f, 0xc0, 0x1f, 0xff, 0x38, 0xf8, 0x1f, 0xff, 0xf8, 0x03,
0xfc, 0x1f, 0xff, 0x80, 0x3f, 0xe0, 0x1f, 0xe0, 0x0f, 0x7f, 0x38, 0xf8,
0x0f, 0x7f, 0xfc, 0x03, 0xfe, 0xff, 0x7f, 0xc0, 0x1f, 0xe0, 0xff, 0xef,
0xff, 0x3f, 0x1c, 0xf8, 0x8f, 0xff, 0xff, 0x01, 0xff, 0xff, 0x1f, 0xc0,
0x1f, 0xf0, 0xff, 0xcf, 0xff, 0x1f, 0x1e, 0xf0, 0x87, 0xff, 0x7f, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x38, 0xf6, 0xff, 0x9b, 0xfb,
0xfe, 0x9f, 0x3e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c,
0x1b, 0xb3, 0x9d, 0xdb, 0x8c, 0x59, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x3a, 0x9b, 0xf9, 0xfd, 0x6d, 0xcc, 0x59, 0x1f, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xbf, 0x8d, 0xd9, 0xfa, 0x6d,
0xc6, 0xb8, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xb1,
0xc7, 0x78, 0xd0, 0x3c, 0x66, 0xb8, 0x0f, 0x00 };
//Sensor symbol bitmap.
PROGMEM const unsigned char LambdaSensorSymbol[] = {
0xfc, 0x3f, 0xfe, 0x7f, 0x3f, 0xfc, 0x3f, 0xfc, 0x3f, 0xfc, 0x3f, 0xfc,
0x3f, 0xfc, 0x3f, 0xfc, 0x1f, 0xf8, 0x1f, 0xf8, 0x1f, 0xf8, 0x3f, 0xfc,
0x3f, 0xfc, 0x7f, 0xfe, 0xfe, 0x7f, 0xfc, 0x3f };
//Battery symbol bitmap.
PROGMEM const unsigned char BatterySymbol[] = {
0xfc, 0x3f, 0xfe, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xcf, 0xf3, 0x07, 0xe0,
0x07, 0xe0, 0x07, 0xe0, 0x07, 0xe0, 0x07, 0xe0, 0x07, 0xe0, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xfe, 0x7f, 0xfc, 0x3f };
//Heater symbol bitmap.
PROGMEM const unsigned char HeaterSymbol[] = {
0xfc, 0x3f, 0xfe, 0x7f, 0xff, 0xff, 0xdf, 0xf6, 0x4f, 0xf2, 0x6f, 0xfb,
0x6f, 0xfb, 0x4f, 0xf2, 0xdf, 0xf6, 0xff, 0xff, 0x07, 0xe0, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xfe, 0x7f, 0xfc, 0x3f };
//Lambda Conversion Lookup Table. (ADC 39-791).
const PROGMEM float Lambda_Conversion[753] {
0.750, 0.751, 0.752, 0.752, 0.753, 0.754, 0.755, 0.755, 0.756, 0.757, 0.758, 0.758, 0.759, 0.760, 0.761, 0.761, 0.762, 0.763, 0.764, 0.764,
0.765, 0.766, 0.766, 0.767, 0.768, 0.769, 0.769, 0.770, 0.771, 0.772, 0.772, 0.773, 0.774, 0.774, 0.775, 0.776, 0.777, 0.777, 0.778, 0.779,
0.780, 0.780, 0.781, 0.782, 0.782, 0.783, 0.784, 0.785, 0.785, 0.786, 0.787, 0.787, 0.788, 0.789, 0.790, 0.790, 0.791, 0.792, 0.793, 0.793,
0.794, 0.795, 0.796, 0.796, 0.797, 0.798, 0.799, 0.799, 0.800, 0.801, 0.802, 0.802, 0.803, 0.804, 0.805, 0.805, 0.806, 0.807, 0.808, 0.808,
0.809, 0.810, 0.811, 0.811, 0.812, 0.813, 0.814, 0.815, 0.815, 0.816, 0.817, 0.818, 0.819, 0.820, 0.820, 0.821, 0.822, 0.823, 0.824, 0.825,
0.825, 0.826, 0.827, 0.828, 0.829, 0.830, 0.830, 0.831, 0.832, 0.833, 0.834, 0.835, 0.836, 0.837, 0.837, 0.838, 0.839, 0.840, 0.841, 0.842,
0.843, 0.844, 0.845, 0.846, 0.846, 0.847, 0.848, 0.849, 0.850, 0.851, 0.852, 0.853, 0.854, 0.855, 0.855, 0.856, 0.857, 0.858, 0.859, 0.860,
0.861, 0.862, 0.863, 0.864, 0.865, 0.865, 0.866, 0.867, 0.868, 0.869, 0.870, 0.871, 0.872, 0.873, 0.874, 0.875, 0.876, 0.877, 0.878, 0.878,
0.879, 0.880, 0.881, 0.882, 0.883, 0.884, 0.885, 0.886, 0.887, 0.888, 0.889, 0.890, 0.891, 0.892, 0.893, 0.894, 0.895, 0.896, 0.897, 0.898,
0.899, 0.900, 0.901, 0.902, 0.903, 0.904, 0.905, 0.906, 0.907, 0.908, 0.909, 0.910, 0.911, 0.912, 0.913, 0.915, 0.916, 0.917, 0.918, 0.919,
0.920, 0.921, 0.922, 0.923, 0.924, 0.925, 0.926, 0.927, 0.928, 0.929, 0.931, 0.932, 0.933, 0.934, 0.935, 0.936, 0.937, 0.938, 0.939, 0.940,
0.941, 0.942, 0.944, 0.945, 0.946, 0.947, 0.948, 0.949, 0.950, 0.951, 0.952, 0.953, 0.954, 0.955, 0.957, 0.958, 0.959, 0.960, 0.961, 0.962,
0.963, 0.965, 0.966, 0.967, 0.969, 0.970, 0.971, 0.973, 0.974, 0.976, 0.977, 0.979, 0.980, 0.982, 0.983, 0.985, 0.986, 0.987, 0.989, 0.990,
0.991, 0.992, 0.994, 0.995, 0.996, 0.998, 0.999, 1.001, 1.003, 1.005, 1.008, 1.010, 1.012, 1.015, 1.017, 1.019, 1.022, 1.024, 1.026, 1.028,
1.030, 1.032, 1.035, 1.037, 1.039, 1.041, 1.043, 1.045, 1.048, 1.050, 1.052, 1.055, 1.057, 1.060, 1.062, 1.064, 1.067, 1.069, 1.072, 1.075,
1.077, 1.080, 1.082, 1.085, 1.087, 1.090, 1.092, 1.095, 1.098, 1.100, 1.102, 1.105, 1.107, 1.110, 1.112, 1.115, 1.117, 1.120, 1.122, 1.124,
1.127, 1.129, 1.132, 1.135, 1.137, 1.140, 1.142, 1.145, 1.148, 1.151, 1.153, 1.156, 1.159, 1.162, 1.165, 1.167, 1.170, 1.173, 1.176, 1.179,
1.182, 1.185, 1.188, 1.191, 1.194, 1.197, 1.200, 1.203, 1.206, 1.209, 1.212, 1.215, 1.218, 1.221, 1.224, 1.227, 1.230, 1.234, 1.237, 1.240,
1.243, 1.246, 1.250, 1.253, 1.256, 1.259, 1.262, 1.266, 1.269, 1.272, 1.276, 1.279, 1.282, 1.286, 1.289, 1.292, 1.296, 1.299, 1.303, 1.306,
1.310, 1.313, 1.317, 1.320, 1.324, 1.327, 1.331, 1.334, 1.338, 1.342, 1.345, 1.349, 1.352, 1.356, 1.360, 1.364, 1.367, 1.371, 1.375, 1.379,
1.382, 1.386, 1.390, 1.394, 1.398, 1.401, 1.405, 1.409, 1.413, 1.417, 1.421, 1.425, 1.429, 1.433, 1.437, 1.441, 1.445, 1.449, 1.453, 1.457,
1.462, 1.466, 1.470, 1.474, 1.478, 1.483, 1.487, 1.491, 1.495, 1.500, 1.504, 1.508, 1.513, 1.517, 1.522, 1.526, 1.531, 1.535, 1.540, 1.544,
1.549, 1.554, 1.558, 1.563, 1.568, 1.572, 1.577, 1.582, 1.587, 1.592, 1.597, 1.601, 1.606, 1.611, 1.616, 1.621, 1.627, 1.632, 1.637, 1.642,
1.647, 1.652, 1.658, 1.663, 1.668, 1.674, 1.679, 1.684, 1.690, 1.695, 1.701, 1.707, 1.712, 1.718, 1.724, 1.729, 1.735, 1.741, 1.747, 1.753,
1.759, 1.764, 1.770, 1.776, 1.783, 1.789, 1.795, 1.801, 1.807, 1.813, 1.820, 1.826, 1.832, 1.839, 1.845, 1.852, 1.858, 1.865, 1.872, 1.878,
1.885, 1.892, 1.898, 1.905, 1.912, 1.919, 1.926, 1.933, 1.940, 1.947, 1.954, 1.961, 1.968, 1.975, 1.983, 1.990, 1.997, 2.005, 2.012, 2.020,
2.027, 2.035, 2.042, 2.050, 2.058, 2.065, 2.073, 2.081, 2.089, 2.097, 2.105, 2.113, 2.121, 2.129, 2.137, 2.145, 2.154, 2.162, 2.171, 2.179,
2.188, 2.196, 2.205, 2.214, 2.222, 2.231, 2.240, 2.249, 2.258, 2.268, 2.277, 2.286, 2.295, 2.305, 2.314, 2.324, 2.333, 2.343, 2.353, 2.363,
2.373, 2.383, 2.393, 2.403, 2.413, 2.424, 2.434, 2.444, 2.455, 2.466, 2.476, 2.487, 2.498, 2.509, 2.520, 2.532, 2.543, 2.554, 2.566, 2.577,
2.589, 2.601, 2.613, 2.625, 2.637, 2.649, 2.662, 2.674, 2.687, 2.699, 2.712, 2.725, 2.738, 2.751, 2.764, 2.778, 2.791, 2.805, 2.819, 2.833,
2.847, 2.861, 2.875, 2.890, 2.904, 2.919, 2.934, 2.949, 2.964, 2.979, 2.995, 3.010, 3.026, 3.042, 3.058, 3.074, 3.091, 3.107, 3.124, 3.141,
3.158, 3.175, 3.192, 3.209, 3.227, 3.245, 3.263, 3.281, 3.299, 3.318, 3.337, 3.355, 3.374, 3.394, 3.413, 3.433, 3.452, 3.472, 3.492, 3.513,
3.533, 3.554, 3.575, 3.597, 3.618, 3.640, 3.662, 3.684, 3.707, 3.730, 3.753, 3.776, 3.800, 3.824, 3.849, 3.873, 3.898, 3.924, 3.950, 3.976,
4.002, 4.029, 4.056, 4.084, 4.112, 4.140, 4.169, 4.198, 4.228, 4.258, 4.288, 4.319, 4.350, 4.382, 4.414, 4.447, 4.480, 4.514, 4.548, 4.583,
4.618, 4.654, 4.690, 4.726, 4.764, 4.801, 4.840, 4.879, 4.918, 4.958, 4.999, 5.040, 5.082, 5.124, 5.167, 5.211, 5.255, 5.299, 5.345, 5.391,
5.438, 5.485, 5.533, 5.582, 5.632, 5.683 ,5.735, 5.788, 5.841, 5.896, 5.953, 6.010, 6.069, 6.129, 6.190, 6.253, 6.318, 6.384, 6.452, 6.521,
6.592, 6.665, 6.740, 6.817, 6.896, 6.976, 7.059, 7.144, 7.231, 7.320, 7.412, 7.506, 7.602, 7.701, 7.803, 7.906, 8.013, 8.122, 8.234, 8.349,
8.466, 8.587, 8.710, 8.837, 8.966, 9.099, 9.235, 9.374, 9.516, 9.662, 9.811, 9.963, 10.119 };
//Function for transfering SPI data to the CJ125.
uint16_t COM_SPI(uint16_t TX_data) {
//Set chip select pin low, chip in use.
digitalWrite(CJ125_CS_PIN, LOW);
//Transmit and receive.
byte highByte = SPI.transfer(TX_data >> 8);
byte lowByte = SPI.transfer(TX_data & 0xff);
//Set chip select pin high, chip not in use.
digitalWrite(CJ125_CS_PIN, HIGH);
//Assemble response in to a 16bit integer and return the value.
uint16_t Response = (highByte << 8) + lowByte;
return Response;
}
//Displays the AFR value on an external narrowband lambda gauge with an (RC-filtered) 0-1V PWM signal from ANALOG_OUTPUT_PIN. 0V = AFR 20.00. 1V = AFR 10.00.
void UpdateAnalogOutput() {
//Local constants.
const float AirFuelRatioOctane = 14.70;
const int maximumOutput = 51; /* 1V */
const int minimumOutput = 0; /* 0V */
//Local variables.
int analogOutput = 0;
float lambdaAFR = Lookup_Lambda(adcValue_UA) * AirFuelRatioOctane;
//Convert lambda value to PWM output.
analogOutput = map(lambdaAFR * 100, 2000, 1000, minimumOutput, maximumOutput);
//Make sure we do not exceed maximum values.
if (analogOutput > maximumOutput) analogOutput = maximumOutput;
if (analogOutput < minimumOutput) analogOutput = minimumOutput;
//Set PWM output.
analogWrite(ANALOG_OUTPUT_PIN, analogOutput);
}
//Lookup Lambda Value.
float Lookup_Lambda(int Input_ADC) {
//Declare and set default return value.
float LAMBDA_VALUE = 0;
//Validate ADC range for lookup table.
if (Input_ADC >= 39 && Input_ADC <= 791) {
LAMBDA_VALUE = pgm_read_float_near(Lambda_Conversion + (Input_ADC-39));
}
if (Input_ADC > 791) {
LAMBDA_VALUE = 10.119;
}
if (Input_ADC < 39) {
LAMBDA_VALUE = 0.750;
}
//Return value.
return LAMBDA_VALUE;
}
//Temperature regulating software (PID).
int CalculateHeaterOutput(int input) {
//Calculate error term.
int error = adcValue_UR_Optimal - input;
//Set current position.
int position = input;
//Calculate proportional term.
float pTerm = -pGain * error;
//Calculate the integral state with appropriate limiting.
iState += error;
if (iState > iMax) iState = iMax;
if (iState < iMin) iState = iMin;
//Calculate the integral term.
float iTerm = -iGain * iState;
//Calculate the derivative term.
float dTerm = -dGain * (dState - position);
dState = position;
//Calculate regulation (PI).
int RegulationOutput = pTerm + iTerm + dTerm;
//Set maximum heater output (full power).
if (RegulationOutput > 255) RegulationOutput = 255;
//Set minimum heater value (cooling).
if (RegulationOutput < 0.0) RegulationOutput = 0;
//Return calculated PWM output.
return RegulationOutput;
}
//Function to transfer current values to front end.
void UpdateSerialOutput() {
//Calculate checksum.
uint16_t checksum = HeaterStatus + hardwareId + CJ125_Status + adcValue_UA + adcValue_UR + adcValue_UB;
//Assembled data.
String txString = (String)HeaterStatus;
txString += ",";
txString += (String)hardwareId;
txString += ",";
txString += (String)CJ125_Status;
txString += ",";
txString += (String)adcValue_UA;
txString += ",";
txString += (String)adcValue_UR;
txString += ",";
txString += (String)adcValue_UB;
txString += ",";
txString += (String)checksum;
//Output values.
Serial.println(txString);
}
//Function to read inputs and update values.
void UpdateInputs() {
//Update CJ125 diagnostic register from SPI.
CJ125_Status = COM_SPI(CJ125_DIAG_REG_REQUEST);
//Update analog inputs.
adcValue_UA = analogRead(UA_ANALOG_INPUT_PIN);
adcValue_UR = analogRead(UR_ANALOG_INPUT_PIN);
adcValue_UB = analogRead(UB_ANALOG_INPUT_PIN);
}
//Function to update user interfaces and output.
void UpdateUI() {
//Local variables.
const float AirFuelRatioOctane = 14.70;
//Sensor is not active.
if (HeaterStatus == 0) {
//Output LED's.
digitalWrite(LED_STATUS_POWER, LOW);
digitalWrite(LED_STATUS_HEATER, LOW);
//Output serial data.
UpdateSerialOutput();
//Output logo to display.
u8g2.firstPage();
do {
u8g2.drawXBMP(0, 16, 128, 32, Logo);
} while ( u8g2.nextPage() );
}
//Sensor is heating up.
if (HeaterStatus == 1) {
//Output LED's.
digitalWrite(LED_STATUS_POWER, HIGH);
digitalWrite(LED_STATUS_HEATER, HIGH);
//Output serial data.
UpdateSerialOutput();
//Output display data.
u8g2.firstPage();
do {
u8g2.drawXBMP(112, 4, 16, 16, LambdaSensorSymbol);
u8g2.drawXBMP(112, 24, 16, 16, BatterySymbol);
u8g2.drawXBMP(112, 44, 16, 16, HeaterSymbol);
} while ( u8g2.nextPage() );
//Delay for flashing LED's.
delay(500);
//Output display data.
u8g2.firstPage();
do {
u8g2.drawXBMP(112, 4, 16, 16, LambdaSensorSymbol);
u8g2.drawXBMP(112, 24, 16, 16, BatterySymbol);
} while ( u8g2.nextPage() );
//Output LED's.
digitalWrite(LED_STATUS_HEATER, LOW);
//Delay for flashing LED's.
delay(500);
}
//Sensor is measuring.
if (HeaterStatus == 2) {
//Output LED's.
digitalWrite(LED_STATUS_POWER, HIGH);
digitalWrite(LED_STATUS_HEATER, HIGH);
//Output serial data.
UpdateSerialOutput();
//Update analog output.
UpdateAnalogOutput();
//Output display data.
u8g2.firstPage();
do {
u8g2.drawXBMP(112, 4, 16, 16, LambdaSensorSymbol);
u8g2.drawXBMP(112, 24, 16, 16, BatterySymbol);
u8g2.drawXBMP(112, 44, 16, 16, HeaterSymbol);
u8g2.setFont(u8g2_font_helvB24_tf);
u8g2.setCursor(0,29);
u8g2.print(Lookup_Lambda(adcValue_UA) * AirFuelRatioOctane, 2);
u8g2.setCursor(0,59);
u8g2.print(Lookup_Lambda(adcValue_UA), 2);
} while ( u8g2.nextPage() );
}
}
//Function to set up device for operation.
void setup() {
//Set up serial communication.
Serial.begin(9600);
//Set up SPI.
SPI.begin(); /* Note, SPI will disable the bult in LED*/
SPI.setClockDivider(SPI_CLOCK_DIV128);
SPI.setBitOrder(MSBFIRST);
SPI.setDataMode(SPI_MODE1);
//Set up digital output pins.
pinMode(CJ125_CS_PIN, OUTPUT);
pinMode(LED_STATUS_POWER, OUTPUT);
pinMode(LED_STATUS_HEATER, OUTPUT);
pinMode(HEATER_OUTPUT_PIN, OUTPUT);
pinMode(ANALOG_OUTPUT_PIN, OUTPUT);
analogWrite(HEATER_OUTPUT_PIN, 0); /* PWM is initially off. */
analogWrite(ANALOG_OUTPUT_PIN, 0); /* PWM is initially off. */
//Initialize display.
u8g2.begin();
//Start main function.
start();
}
void start() {
//Reset initial values.
digitalWrite(CJ125_CS_PIN, HIGH);
digitalWrite(LED_STATUS_POWER, LOW);
digitalWrite(LED_STATUS_HEATER, LOW);
analogWrite(HEATER_OUTPUT_PIN, 0);
//Start of operation. (Test LED's).
digitalWrite(LED_STATUS_POWER, HIGH);
digitalWrite(LED_STATUS_HEATER, HIGH);
delay(200);
digitalWrite(LED_STATUS_POWER, LOW);
digitalWrite(LED_STATUS_HEATER, LOW);
//Update heater status to off.
HeaterStatus = 0;
//Wait until everything is ready. Read CJ125 multiple times with delay in between to let it initialize. Otherwise responds OK.
while (adcValue_UB < UBAT_MIN || CJ125_Status != CJ125_DIAG_REG_STATUS_OK) {
//Update Values.
UpdateInputs();
//Update frontends.
UpdateUI();
//Delay.
delay(100);
}
//Set CJ125 in calibration mode.
COM_SPI(CJ125_INIT_REG1_MODE_CALIBRATE);
//Let values settle.
delay(500);
//Store optimal values before leaving calibration mode.
adcValue_UA_Optimal = analogRead(UA_ANALOG_INPUT_PIN);
adcValue_UR_Optimal = analogRead(UR_ANALOG_INPUT_PIN);
//Update analog output, display the optimal value.
adcValue_UA = adcValue_UA_Optimal;
UpdateAnalogOutput();
//Set CJ125 in normal operation mode.
//COM_SPI(CJ125_INIT_REG1_MODE_NORMAL_V8); /* V=0 */
COM_SPI(CJ125_INIT_REG1_MODE_NORMAL_V17); /* V=1 */
/* Heat up sensor. This is described in detail in the datasheet of the LSU 4.9 sensor with a
* condensation phase and a ramp up face before going in to PID control. */
//Update heater status to heating.
HeaterStatus = 1;
//Calculate supply voltage.
float SupplyVoltage = (((float)adcValue_UB / 1023 * 5) / 10000) * 110000;
//Condensation phase, 2V for 5s.
int CondensationPWM = (2 / SupplyVoltage) * 255;
analogWrite(HEATER_OUTPUT_PIN, CondensationPWM);
int t = 0;
while (t < 5 && adcValue_UB > UBAT_MIN) {
//Update Values.
UpdateInputs();
//Update frontends.
UpdateUI();
t += 1;
}
//Ramp up phase, +0.4V / s until 100% PWM from 8.5V.
float UHeater = 8.5;
while (UHeater < 13.0 && adcValue_UB > UBAT_MIN && adcValue_UR > adcValue_UR_Optimal) {
//Update Values.
UpdateInputs();
//Update frontends.
UpdateUI();
//Set heater output during ramp up.
CondensationPWM = (UHeater / SupplyVoltage) * 255;
if (CondensationPWM > 255) CondensationPWM = 255; /*If supply voltage is less than 13V, maximum is 100% duty cycle*/
analogWrite(HEATER_OUTPUT_PIN, CondensationPWM);
//Increment Voltage.
UHeater += 0.4;
}
//Update heater status to regulating.
HeaterStatus = 2;
}
//Infinite loop.
void loop() {
//Update Values.
UpdateInputs();
//Display on serial port at defined rate. Comma separate values, readable by frontends.
if ( (100 / SERIAL_RATE) == serial_counter) {
//Reset counter.
serial_counter = 0;
//Update frontends.
UpdateUI();
}
//Adjust PWM output by calculated PID regulation.
if (adcValue_UR < 500 && adcValue_UB > UBAT_MIN) {
//Calculate and set new heater output.
HeaterOutput = CalculateHeaterOutput(adcValue_UR);
analogWrite(HEATER_OUTPUT_PIN, HeaterOutput);
} else {
//Re-start() and wait for power.
start();
}
//Increment serial output counter and delay for next cycle. The PID requires to be responsive but we don't need to flood the serial port.
serial_counter++;
delay(10);
}